HOME SWITCHER

My low-budget router has just crashed, and there is no way to reset the beast remotely via a network. Never fear – an X10 module, controlled by a web GUI with an Ajax interface, can actuate the mains switch.

Regular readers will recall that last month’s Perl column relied on X10 technology to transmit switching signals over normal power lines at home. In this article, I will extend the scenario to include three new devices with X10 receivers: my DSL modem, my DSL router, and my TiVo digital video recorder. The lights in the bedroom and living room are already connected to X10 boxes.

Figure 2 shows the results of running the scripts in this article. As you can see, the browser displays intuitive names for the devices in question, and a button in the right-hand column of the table for each row lights up green or red, depending on the current device status. Clicking the button toggles the device state. This all relies on state-of-the-art Ajax technology – the browser does not need to reload the whole web page, just single fields that have changed.

Today’s digital multimeters can do more than measure current and voltage. Multimeters also measure capacity and temperature. An inexpensive multimeter can talk to your PC via the serial port, and simple Perl scripts let you read and visualize data in neat charts.